Re-Calibrating the machine?

#1

Hi all! I am fairly new (less then a year) to all this and own a Shapeoko XXL. I have been going along and everything seems fine. However, this past weekend I started a project that has some fairly tight tolerances, an award plaque with lettering near the edge. I ran it and noticed that the lettering was going too far. So I scrapped it and tried again. This time I made sure the material was the exact dimensions, 11.25 inches, but when I manually jog the machine from zero up the y axis 11.25 inches, it goes off the material about .1 inch.

I thought that was weird so I tried the circle/diamond/square test to see how calibrated the machine was and it turned out great.

Square-3.99 inches and was supposed to be 4 inches
Diamond- 2.49 inches and was supposed to be 2.5 inches
Circle- 2 inches exactly

Any ideas?

#2

Have you calibrated for belt stretch per:

First though, check and see if you need new belts we’ll cover them under warranty — if you have steel core even if you’re out of warranty contact support@carbide3d.com

#3

Yeah, just did that as well. my cheap calipers seem to think that it’s good, well about 149mm and not 150 but I think that’s because of the way the calipers fit into the Vbit holes.

#4

You should be cutting the holes so that it’s the caliper tips which determine how the holes are measured and nothing else.

#5

Yep, I made the holes too big and the calipers were kind of weird in them. However, I feel fairly confident in the results. Even if it was 1 mm off over 150, I don’t think that translates into .15 inches over 11.25 inches. But I think I will try it again tomorrow. Sometimes stepping away from the problem for a while helps.

#6

That’s still quit a bit out. .015 = 3.8mm. The machine should easily be able to maintain < .005" over 16"
2mm over twelve inches is still well above that.

#7

@gonziago Exactly how are you zeroing XY?
Is the CENTER of your endmill directly over the edge of the stock?

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#8

Yep, I was zeroing using a 60 degree Vbit and it was right over the corner. I kind of fudged the math for this one. Made the design just a bit smaller and zero’ed a bit low. So there was some error both below and above, however because the design was smaller it still all fit on the piece. Not the greatest resolution, but I was able to finish and will continue to work on the machine this weekend.

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